Porcellanopagurus edwardsi
Encyclopedia
Porcellanopagurus edwardsi is a species of hermit crab
that lives in the waters around New Zealand
and its Subantarctic Islands
.
, Campbell Islands, Snares Islands, Stewart Island and along the coast of New Zealand's South Island
. The closely related species P. filholi has a more northerly distribution, overlapping with that of P. edwardsi only in the region of the Banks Peninsula
.
in 1885 as the only species in a new genus Porcellanopagurus
; 12 further species have since been described.
, but its abdomen is bent back over the carapace, so that the pleopods are dorsally situated. The abdomen is "grossly distorted", and is usually covered by the shell of a bivalve
or limpet
, in contrast to the gastropod shell
used by most hermit crabs. The cephalothorax
is flattened and extends outwards in a number of lobes, the largest of which is the rostrum
at the front of the animal.
Hermit crab
Hermit crabs are decapod crustaceans of the superfamily Paguroidea. Most of the 1100 species possess an asymmetrical abdomen which is concealed in an empty gastropod shell that is carried around by the hermit crab.-Description:...
that lives in the waters around New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and its Subantarctic Islands
New Zealand sub-antarctic islands
The five southernmost groups of the New Zealand Outlying Islands form the New Zealand Sub-Antarctic islands. These islands are collectively designated as an UNESCO World Heritage Site....
.
Distribution
Porcellanopagurus edwardsi is found around the Auckland IslandsAuckland Islands
The Auckland Islands are an archipelago of the New Zealand Sub-Antarctic Islands and include Auckland Island, Adams Island, Enderby Island, Disappointment Island, Ewing Island, Rose Island, Dundas Island and Green Island, with a combined area of...
, Campbell Islands, Snares Islands, Stewart Island and along the coast of New Zealand's South Island
South Island
The South Island is the larger of the two major islands of New Zealand, the other being the more populous North Island. It is bordered to the north by Cook Strait, to the west by the Tasman Sea, to the south and east by the Pacific Ocean...
. The closely related species P. filholi has a more northerly distribution, overlapping with that of P. edwardsi only in the region of the Banks Peninsula
Banks Peninsula
Banks Peninsula is a peninsula of volcanic origin on the east coast of the South Island of New Zealand. It has an area of approximately and encompasses two large harbours and many smaller bays and coves...
.
Taxonomy
Porcellanopagurus edwardsi was described by Henri FilholHenri Filhol
Henri Filhol was a French medical doctor, malacologist and naturalist. He served as the expedition doctor and naturalist on the French 1874 Transit of Venus expedition to Campbell Island, New Zealand, with a peak on the island, Filhol Peak, being named after him...
in 1885 as the only species in a new genus Porcellanopagurus
Porcellanopagurus
Porcellanopagurus is a genus of hermit crabs, containing the following species:*Porcellanopagurus adelocercus McLaughlin & Hogarth, 1998*Porcellanopagurus belauensis Suzuki & Takeda, 1987...
; 12 further species have since been described.
Description
Unlike most hermit crabs, Porcellanopagurus edwardsi is almost symmetricalSymmetry
Symmetry generally conveys two primary meanings. The first is an imprecise sense of harmonious or aesthetically pleasing proportionality and balance; such that it reflects beauty or perfection...
, but its abdomen is bent back over the carapace, so that the pleopods are dorsally situated. The abdomen is "grossly distorted", and is usually covered by the shell of a bivalve
Bivalvia
Bivalvia is a taxonomic class of marine and freshwater molluscs. This class includes clams, oysters, mussels, scallops, and many other families of molluscs that have two hinged shells...
or limpet
Limpet
Limpet is a common name for a number of different kinds of saltwater and freshwater snails ; it is applied to those snails that have a simple shell which is more or less conical in shape, and either is not spirally coiled, or appears not to be coiled in the adult snails.The name limpet is most...
, in contrast to the gastropod shell
Gastropod shell
The gastropod shell is a shell which is part of the body of a gastropod or snail, one kind of mollusc. The gastropod shell is an external skeleton or exoskeleton, which serves not only for muscle attachment, but also for protection from predators and from mechanical damage...
used by most hermit crabs. The cephalothorax
Cephalothorax
The cephalothorax is a tagma of various arthropods, comprising the head and the thorax fused together, as distinct from the abdomen behind. The word cephalothorax is derived from the Greek words for head and thorax...
is flattened and extends outwards in a number of lobes, the largest of which is the rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....
at the front of the animal.